The present invention relates to a system for recording information on photographic image density, and more particularly, to a system which eliminates information on the density of unimportant areas of a photographic image, with the result that the possible noise that will interfere with the drawing of density information from the important area of the photographic image is reduced.
Photographic printing devices or other photographic devices are equipped with a recorder for photographic image density (hereunder simply referred to as density). This machine is capable of efficient recording of the density of each image frame (hereunder simply referred to as a frame) of an original film to be printed such as a negative or positive film (hereunder simply referred to as negative film or the like). The most important thing about this recorder is that it be capable of recording the same density information from the same scene on the negative film or the like irrespective of any change in the background. To meet this end, the conventional recorder draws the density information only from the center of the frame of the negative film or the like because it is empirically established that the principal part of the scene is highly probably positioned in the center of the frame. However, this practice causes a serious error if the principal part of the scene is not in the center of the frame.